The invention relates to a suspension element comprising:
a base which is provided at one side with a first coupling means with a first retention bracket and a second coupling means with a second retention bracket;
which retention brackets are arranged on either side of a plane O which is perpendicular to the base.
The invention also relates to a luminaire.
Such a suspension element, which is provided on a luminaire, is known from WO 97/35416. The two retention brackets of the known suspension element are U-shaped and each have two limbs. Each retention bracket is situated with one limb in the base, while the other limb is at a distance from the base. The suspension element is designed for cooperating by means of its U-shaped retention brackets with a T-shaped rail which is, for example, fastened to the ceiling. For this purpose, the suspension element is moved with its U-shaped retention brackets around the two sides of the T-shaped rail through rotation of the base. The luminaire provided with the known suspension element can thus be suspended. It is furthermore envisaged with the known suspension element that the luminaire is freely displaceable over the T-shaped rail by sliding the suspension element over the T-shaped rail without any appreciable damage to the rail. It is a disadvantage of the known suspension element that a special profile is required for this, which has a comparatively precise fit with respect to the T-shaped rail.
The invention has for its object to counteract the above disadvantage. For this purpose, the suspension element of the kind described in the opening paragraph is characterized in that at least one retention bracket is concave and hook-shaped with respect to the base, and in that the retention brackets are connected to the base via a mechanical guiding element rising from the base for accommodating a fastening element, initially positioned between the retention brackets, in a space defined by the retention brackets by means of at least substantially frictionless displacements along the guiding elements. A series of displacements comprises, for example, a displacement of the fastening element and the suspension element towards one another in a direction along or in the plane O, a displacement at least partly in a direction transverse to the plane O of this fastening element, as a result of which a subsequent displacement of the fastening element and the suspension element away from one another in a direction along or in the plane O causes the fastening element to enter the space defined by the retention brackets. The suspension element is designed for cooperating by means of its retention brackets with the fastening element. No specific shape is required for the concave, hooked retention bracket if the suspension element is to function, so that a special profile of the fastening element is not required either. This means that in principle any rod and/or wire-shaped fastening element is suitable for cooperating with the suspension element according to the invention so as to achieve an interconnection of the suspension element and the fastening element. A wide variety of suitable embodiments of the suspension element is also made possible. Since an accurate dimensioning of the suspension element is not required, a manufacture of the suspension element is comparatively simple. In embodiments of the suspension element, the guiding element of the first retention bracket and the guiding element of the second retention bracket may be designed as separate guiding elements or as a joint guiding element. It was found with the use of a suspension element in which the mechanical guiding element of the first retention bracket is separate from the mechanical guiding element of the second retention bracket that an improved guidance of the displacement is obtained. A flexible suspension of the luminaire is also achieved with the suspension element, and a displacement over the fastening element can be easily carried out.
In an embodiment of the suspension element, the mechanical guiding element extends from the first retention bracket to the base and obliquely relative to the plane O up to or beyond the plane O, such that the fastening element is forced from the plane O by the guiding element during the displacement of the fastening element and the suspension element towards one another in a direction along or in the plane O. The word xe2x80x9cobliquelyxe2x80x9d is understood to denote an angle of at most 45xc2x0 between the guiding element and the plane O. Another disadvantage of the known suspension element is that it can comparatively easily get detached from the rail, for example during alignment of the luminaire fixed thereto, and may subsequently drop. This means that the known luminaire has a comparatively high risk of becoming damaged owing to dropping and/or of causing damage to its surroundings. In the suspension element according to the invention, the fastening element is brought between the retention brackets for coupling the suspension element and the fastening element, and subsequently is brought into a space defined by the retention brackets by means of a combination of mutual movements, preferably a combination of a rotary movement and translations about and along, respectively, an axis which is perpendicular to the base. It is immaterial for a cooperation between the suspension element and the fastening element whether it is the suspension element or the fastening element that performs the envisaged relative (rotary) movements for coupling. Decoupling of the suspension element and the fastening element requires movements of the suspension and fastening elements which are substantially inverse to the coupling movements. The risk that these inverse movements are inadvertently carried out is comparatively small, which achieves that the risk of the suspension element getting loose is considerably reduced, and is at least substantially smaller than the risk of the known suspension element getting loose. The suspension of a luminaire connected to the suspension element has thus become more reliable. It was found that the risk of an inadvertent detachment is smaller especially if a rotation is required for the undesirable movement. The suspension is made even more reliable thereby. The oblique design of the guiding element as it were automatically promotes the envisaged mutual rotation during the insertion of the fastening element into the space defined by the retention brackets and the subsequent movement towards one another of the fastening element and the suspension element. An additional advantage of a guiding element designed in this manner is that it counteracts any inadvertent decoupling of the fastening element and the suspension element in that it renders an undesirable, inverse mutual rotary movement more difficult. The suspension of the suspension element has been made even more reliable thereby.
In a further embodiment of the suspension element, the retention brackets each have a first end and a second, free end, said retention brackets being concave and hook-shaped with respect to the base, with the first retention bracket directed oppositely to the second retention bracket when traversing the relevant retention bracket from the first end to the free end. A shift towards and/or rotation relative to the free end by the fastening element, resulting in an inadvertent (partial) detachment of the suspension element, is counteracted thereby.
In a yet further embodiment of the suspension element, the projection of the free end and/or of the first end of the first retention bracket, in a perpendicular projection on the plane O, is situated on or between the projections of the free end and the first end of the second retention bracket. The introduction of the fastening element into the space defined by the retention brackets is made simpler thereby. It is also achieved that the curved portions lie substantially in one another""s extended directions relative to the perpendicular on the plane O. This gives the suspension element the advantage that a shifting of the suspension element over the fastening element along the perpendicular to the plane O takes place comparatively smoothly, which promotes a simple positioning of the suspension element and an object coupled thereto.
In a favorable embodiment of the suspension element, the free end has an internally beveled side edge. The envisaged movement necessary for introducing the fastening element into the space defined by the retention brackets is facilitated thereby.
In a further embodiment of the suspension element, the projection of the first retention bracket coincides at least substantially with the projection of the second retention bracket in a perpendicular projection on the plane O. The introduction into the space defined by the retention brackets with some clearance is made easier thereby. It is also achieved that the retention brackets lie in one another""s extended directions with respect to the perpendicular to the plane O. This gives the suspension element the advantage that shifting of the suspension element over the fastening element along the perpendicular to the plane O proceeds comparatively smoothly, which promotes a simple positioning of the suspension element and an object coupled thereto.
In another embodiment of the suspension element, the base is a flat plate, whereby a more stable suspension is achieved when subjected to forces in directions lying in the plane of the base of the object coupled to the suspension element. Preferably, the base is substantially circular, because this renders possible a comparatively good guiding of the suspension element during the envisaged rotary movement by means of a flange construction.
In a yet further favorable embodiment of the suspension element, the base is provided with an opening between the coupling means, through which opening the suspension element can be mounted in a simple manner to another object, for example a luminaire, for example by means of a screw passed through said opening. The opening may alternatively be used, for example, for the passage and resulting guidance of an electric cable which is used for electrically connecting the lamp to be accommodated in the luminaire. When the suspension element itself is used, it is possible to fasten the suspension element to a wall or ceiling via its opening in a simple manner, for example by means of a screw, in a permanently rotary manner.
Preferably, the suspension element is manufactured from metal or from synthetic resin. If the suspension element is made from metal, the suspension element may be manufactured in one piece by means of a stamping and bending process, for which a suitable material is, for example, steel plating. If the suspension element is made from synthetic resin, it may be manufactured in a comparatively simple manner in an injection molding process, for which a suitable material is, for example, PA-6, i.e. nylon-6 reinforced with 20% by weight of glass fiber.
The suspension element is preferably used in a luminaire comprising at least one suspension element as described above and further provided with means for accommodating an electric lamp in the housing. A reliable suspension of the luminaire is required especially in circumstances in which the luminaire is subject to violent movements, for example in outdoor applications such as a gas station or on a ship. Alternatively, the suspension element may be used to advantage for suspending other objects comprising a suspension attachment, which suspension attachment is to be introduced into the space defined by the curved portions of the retention brackets. Examples of applications with such objects are a curtain rod or a flexible guide for an electric cable along a wall and/or ceiling, with the suspension elements being fastened with rotation possibility to a wall or ceiling.